Clean air advocates cheer as Mary Anne Hitt, director of the Sierra Club's Beyond Coal Campaign, speaks at a rally outside an Environmental Protection Agency hearing, Tuesday, July 29, 2014, in Atlanta. Utility and coal companies are expected to argue Tuesday against proposals from the Obama administration that would force a 30 percent cut in carbon dioxide emissions by the year 2030 from 2005 levels. The EPA is holding three public hearings on the proposal in Atlanta, Denver and Washington. (AP Photo/David Goldman)

Sturgill, a retired coal miner from Harlan County, Kentucky, who traveled to a public hearing about the rules Tuesday in Denver, told the EPA that coal-fired plants are crippling his health and that of the public. Sturgill said he suffers from black lung and other respiratory diseases.

"The rule does not do nearly enough to protect the health of the front-line communities," he said. "We're dying, literally dying, for you to help us."

But at the same hearing, John Kinkaid, a Moffat County, Colorado, commissioner, told the EPA that the rules would devastate his area, home to a major power plant. "Energy is the lifeblood of our economy. Moffat County deserves better than to be turned into another Detroit, Michigan," he said.

The sharply divergent views about the proposed rules were among the many different comments made as the EPA launched hearings Tuesday in Denver, Atlanta and Washington, D.C., on President Barack Obama's plan to cut carbon-dioxide emissions by 30 percent by 2030, with 2005 levels as the starting point. The rules are intended to curb global warming.

Utility and coal company representatives said the rules were unclear and unreasonable, and they warned that jobs and communities could suffer. Renewable-energy executives said their industry will bring jobs, profits and innovations. Grandparents admonished the EPA to do more to protect children.

Georgia utility regulator Lauren "Bubba" McDonald told the EPA in Atlanta that the rules are an unnecessary intervention by the federal government.

"Please leave us alone," McDonald said. "We set these goals ourselves, and we know how to achieve them."

But Jim Doyle, a former Commerce Department official in the Clinton administration, said at the Atlanta hearing that the benefits of fighting climate change outweigh the potential costs of extreme weather blamed on global warming.

"Over the past four years, American factories have been disrupted by typhoons in Thailand, hurricanes in the Gulf of Mexico, droughts in Texas, tornadoes in Kentucky, falling water levels across the Great Lakes and flooding in the Northeast," he said.

The hearings in Denver, Atlanta and Washington will continue Wednesday, and a hearing in Pittsburgh will start on Thursday. The EPA expects 1,600 people to speak in the four cities and has already received more than 300,000 written comments, which will be accepted until Oct. 16.